How to Minimize Oil Canning on Metal Roofs and Walls
Oil canning is a common issue and an aesthetic concern on construction projects that involve single skin walls or roof panels and/or large flashings made from single skin (1 layer) or aluminum or steel flat sheets. Oil canning can occur with steel, aluminum, zinc or copper construction materials.
In general, the occurrence of oil canning with these products cannot be completely eliminated, only reduced or its appearance minimized. Oil canning is inherent when using certain products and is NOT an installation defect. Most manufacturers will specifically say that oil canning is not a reason for product rejection.
Four Ways to Help Reduce Oil Canning in Roofs and Walls
1. Choose a roof panel that offers striations or pencil ribs.
Striations or pencil ribs are rolled into the panel during the roll-forming process and create relief in the flat surface. This option will greatly reduce the effects of oil canning. While these features do not add cost, they must be selected ahead of time and cannot be added after the panel is manufactured. Overall, adding pencil ribs and striations is the most effective option to help reduce oil canning and does not increase the project cost. Click now for PCG Roof Panel insights.
2. Choose a wall panel with pencil ribs.
This mainly applies to a 12” flush wall panel or another panel with a large flat surface (see below). Typically, oil canning is not an issue with a corrugated panel. As with the roof panels, we and our partner manufacturers confidently recommend selecting a panel with pencil ribs formed into the profile. This is the best way to help minimize the oil canning that is inherent in the panel. Click now for PCG Wall Panel insights.
3. Use ACM or aluminum composite material instead of a single skin panel for walls.
ACM was designed to provide a large flat metal surface without oil canning. While more expensive than traditional single skin panels, nothing looks like ACM except ACM. Click now for PCG ACM insights.
4. Use a thicker gauge.
While not the best option, sometimes using a thicker gauge material such as 22GA for steel or 040 aluminum can help reduce oil canning as well.
Factors Affecting Oil Canning
Expansion and contraction.
Metal naturally expands (grows larger) and contracts (shrinks) during changes in temperature. This is why the effects and severity of oil canning may change throughout a day or season depending on the outside temperature or even the direction of the sun.
Substrate.
One common misconception is that metal can hide imperfections in the framework/sheathing that is attached to in the field. Nothing could be further from the truth. A single skin metal panel or flashing will telegraph any imperfections in the substrate behind it. This is why it is so important for the framework and sheathing installation be as plumb and flat as possible.
Here are two side examples of wall panels with and without pencil ribs that show the difference in the appearance of oil canning.
Oil Canning with Pencil Ribs
Remember, oil canning is a common visual phenomenon where metal panels and roofs appear wavy or distorted, particularly in flat areas. With proper material preparation and expert installation, oil canning is a minor cosmetic issue that does not affect the structural integrity of the metal.
Working with Pierre Construction Group project managers is the best way to prepare the roof or panel to minimize the impact of oil canning. Contact us with your questions about this common construction issue.